How to apply force repulsion on map's labels so they find their right places automatically ?
Bostock' "Let's Make a Map"
Mike Bostock's Let's Make a Map (screenshot below). By default, labels are put at the point's coordinates and polygons/multipolygons's path.centroid(d) + a simple left or right align, so they frequently enter in conflict.
Handmade label placements
One improvement I met requires to add an human made IF fixes, and to add as many as needed, such :
.attr("dy", function(d){ if(d.properties.name==="Berlin") {return ".9em"} })
The whole become increasingly dirty as the number of labels to reajust increase :
//places's labels: point objects
svg.selectAll(".place-label")
.data(topojson.object(de, de.objects.places).geometries)
.enter().append("text")
.attr("class", "place-label")
.attr("transform", function(d) { return "translate(" + projection(d.coordinates) + ")"; })
.attr("dy", ".35em")
.text(function(d) { if (d.properties.name!=="Berlin"&&d.properties.name!=="Bremen"){return d.properties.name;} })
.attr("x", function(d) { return d.coordinates[0] > -1 ? 6 : -6; })
.style("text-anchor", function(d) { return d.coordinates[0] > -1 ? "start" : "end"; });
//districts's labels: polygons objects.
svg.selectAll(".subunit-label")
.data(topojson.object(de, de.objects.subunits).geometries)
.enter().append("text")
.attr("class", function(d) { return "subunit-label " + d.properties.name; })
.attr("transform", function(d) { return "translate(" + path.centroid(d) + ")"; })
.attr("dy", function(d){
//handmade IF
if( d.properties.name==="Sachsen"||d.properties.name==="Thüringen"|| d.properties.name==="Sachsen-Anhalt"||d.properties.name==="Rheinland-Pfalz")
{return ".9em"}
else if(d.properties.name==="Brandenburg"||d.properties.name==="Hamburg")
{return "1.5em"}
else if(d.properties.name==="Berlin"||d.properties.name==="Bremen")
{return "-1em"}else{return ".35em"}}
)
.text(function(d) { return d.properties.name; });
Need for better solution
That's just not manageable for larger maps and sets of labels. How to add force repulsions to these both classes: .place-label and .subunit-label?
This issue is quite a brain storming as I haven't deadline on this, but I'am quite curious about it. I was thinking about this question as a basic D3js implementation of Migurski/Dymo.py. Dymo.py's README.md documentation set a large set of objectives, from which to select the core needs and functions (20% of the work, 80% of the result).
Initial placement: Bostock give a good start with left/right positionning relative to the geopoint.
Inter-labels repulsion: different approach are possible, Lars & Navarrc proposed one each,
Labels annihilation: A label annihilation function when one label's overall repulsion is too intense, since squeezed between other labels, with the priority of annihilation being either random or based on a population data value, which we can get via NaturalEarth's .shp file.
[Luxury] Label-to-dots repulsion: with fixed dots and mobile labels. But this is rather a luxury.
I ignore if label repulsion will work across layers and classes of labels. But getting countries labels and cities labels not overlapping may be a luxury as well.
In my opinion, the force layout is unsuitable for the purpose of placing labels on a map. The reason is simple -- labels should be as close as possible to the places they label, but the force layout has nothing to enforce this. Indeed, as far as the simulation is concerned, there is no harm in mixing up labels, which is clearly not desirable for a map.
There could be something implemented on top of the force layout that has the places themselves as fixed nodes and attractive forces between the place and its label, while the forces between labels would be repulsive. This would likely require a modified force layout implementation (or several force layouts at the same time), so I'm not going to go down that route.
My solution relies simply on collision detection: for each pair of labels, check if they overlap. If this is the case, move them out of the way, where the direction and magnitude of the movement is derived from the overlap. This way, only labels that actually overlap are moved at all, and labels only move a little bit. This process is iterated until no movement occurs.
The code is somewhat convoluted because checking for overlap is quite messy. I won't post the entire code here, it can be found in this demo (note that I've made the labels much larger to exaggerate the effect). The key bits look like this:
function arrangeLabels() {
var move = 1;
while(move > 0) {
move = 0;
svg.selectAll(".place-label")
.each(function() {
var that = this,
a = this.getBoundingClientRect();
svg.selectAll(".place-label")
.each(function() {
if(this != that) {
var b = this.getBoundingClientRect();
if(overlap) {
// determine amount of movement, move labels
}
}
});
});
}
}
The whole thing is far from perfect -- note that some labels are quite far away from the place they label, but the method is universal and should at least avoid overlap of labels.
One option is to use the force layout with multiple foci. Each foci must be located in the feature's centroid, set up the label to be attracted only by the corresponding foci. This way, each label will tend to be near of the feature's centroid, but the repulsion with other labels may avoid the overlapping issue.
For comparison:
M. Bostock's "Lets Make a Map" tutorial (resulting map),
my gist for an Automatic Labels Placement version (resulting map) implementing the foci's strategy.
The relevant code:
// Place and label location
var foci = [],
labels = [];
// Store the projected coordinates of the places for the foci and the labels
places.features.forEach(function(d, i) {
var c = projection(d.geometry.coordinates);
foci.push({x: c[0], y: c[1]});
labels.push({x: c[0], y: c[1], label: d.properties.name})
});
// Create the force layout with a slightly weak charge
var force = d3.layout.force()
.nodes(labels)
.charge(-20)
.gravity(0)
.size([width, height]);
// Append the place labels, setting their initial positions to
// the feature's centroid
var placeLabels = svg.selectAll('.place-label')
.data(labels)
.enter()
.append('text')
.attr('class', 'place-label')
.attr('x', function(d) { return d.x; })
.attr('y', function(d) { return d.y; })
.attr('text-anchor', 'middle')
.text(function(d) { return d.label; });
force.on("tick", function(e) {
var k = .1 * e.alpha;
labels.forEach(function(o, j) {
// The change in the position is proportional to the distance
// between the label and the corresponding place (foci)
o.y += (foci[j].y - o.y) * k;
o.x += (foci[j].x - o.x) * k;
});
// Update the position of the text element
svg.selectAll("text.place-label")
.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; });
});
force.start();
While ShareMap-dymo.js may work, it does not appear to be very well documented. I have found a library that works for the more general case, is well documented and also uses simulated annealing: D3-Labeler
I've put together a usage sample with this jsfiddle.The D3-Labeler sample page uses 1,000 iterations. I have found this is rather unnecessary and that 50 iterations seems to work quite well - this is very fast even for a few hundred data points. I believe there is room for improvement both in the way this library integrates with D3 and in terms of efficiency, but I wouldn't have been able to get this far on my own. I'll update this thread should I find the time to submit a PR.
Here is the relevant code (see the D3-Labeler link for further documentation):
var label_array = [];
var anchor_array = [];
//Create circles
svg.selectAll("circle")
.data(dataset)
.enter()
.append("circle")
.attr("id", function(d){
var text = getRandomStr();
var id = "point-" + text;
var point = { x: xScale(d[0]), y: yScale(d[1]) }
var onFocus = function(){
d3.select("#" + id)
.attr("stroke", "blue")
.attr("stroke-width", "2");
};
var onFocusLost = function(){
d3.select("#" + id)
.attr("stroke", "none")
.attr("stroke-width", "0");
};
label_array.push({x: point.x, y: point.y, name: text, width: 0.0, height: 0.0, onFocus: onFocus, onFocusLost: onFocusLost});
anchor_array.push({x: point.x, y: point.y, r: rScale(d[1])});
return id;
})
.attr("fill", "green")
.attr("cx", function(d) {
return xScale(d[0]);
})
.attr("cy", function(d) {
return yScale(d[1]);
})
.attr("r", function(d) {
return rScale(d[1]);
});
//Create labels
var labels = svg.selectAll("text")
.data(label_array)
.enter()
.append("text")
.attr("class", "label")
.text(function(d) {
return d.name;
})
.attr("x", function(d) {
return d.x;
})
.attr("y", function(d) {
return d.y;
})
.attr("font-family", "sans-serif")
.attr("font-size", "11px")
.attr("fill", "black")
.on("mouseover", function(d){
d3.select(this).attr("fill","blue");
d.onFocus();
})
.on("mouseout", function(d){
d3.select(this).attr("fill","black");
d.onFocusLost();
});
var links = svg.selectAll(".link")
.data(label_array)
.enter()
.append("line")
.attr("class", "link")
.attr("x1", function(d) { return (d.x); })
.attr("y1", function(d) { return (d.y); })
.attr("x2", function(d) { return (d.x); })
.attr("y2", function(d) { return (d.y); })
.attr("stroke-width", 0.6)
.attr("stroke", "gray");
var index = 0;
labels.each(function() {
label_array[index].width = this.getBBox().width;
label_array[index].height = this.getBBox().height;
index += 1;
});
d3.labeler()
.label(label_array)
.anchor(anchor_array)
.width(w)
.height(h)
.start(50);
labels
.transition()
.duration(800)
.attr("x", function(d) { return (d.x); })
.attr("y", function(d) { return (d.y); });
links
.transition()
.duration(800)
.attr("x2",function(d) { return (d.x); })
.attr("y2",function(d) { return (d.y); });
For a more in depth look at how D3-Labeler works, see "A D3 plug-in for automatic label placement using simulated
annealing"
Jeff Heaton's "Artificial Intelligence for Humans, Volume 1" also does an excellent job at explaining the simulated annealing process.
You might be interested in the d3fc-label-layout component (for D3v5) that is designed exactly for this purpose. The component provides a mechanism for arranging child components based on their rectangular bounding boxes. You can apply either a greedy or simulated annealing strategy in order to minimise overlaps.
Here's a code snippet which demonstrates how to apply this layout component to Mike Bostock's map example:
const labelPadding = 2;
// the component used to render each label
const textLabel = layoutTextLabel()
.padding(labelPadding)
.value(d => d.properties.name);
// a strategy that combines simulated annealing with removal
// of overlapping labels
const strategy = layoutRemoveOverlaps(layoutGreedy());
// create the layout that positions the labels
const labels = layoutLabel(strategy)
.size((d, i, g) => {
// measure the label and add the required padding
const textSize = g[i].getElementsByTagName('text')[0].getBBox();
return [textSize.width + labelPadding * 2, textSize.height + labelPadding * 2];
})
.position(d => projection(d.geometry.coordinates))
.component(textLabel);
// render!
svg.datum(places.features)
.call(labels);
And this is a small screenshot of the result:
You can see a complete example here:
http://bl.ocks.org/ColinEberhardt/389c76c6a544af9f0cab
Disclosure: As discussed in the comment below, I am a core contributor of this project, so clearly I am somewhat biased. Full credit to the other answers to this question which gave us inspiration!
For 2D case
here are some examples that do something very similar:
one http://bl.ocks.org/1691430
two http://bl.ocks.org/1377729
thanks Alexander Skaburskis who brought this up here
For 1D case
For those who search a solution to a similar problem in 1-D i can share my sandbox JSfiddle where i try to solve it. It's far from perfect but it kind of doing the thing.
Left: The sandbox model, Right: an example usage
Here is the code snippet which you can run by pressing the button in the end of the post, and also the code itself. When running, click on the field to position the fixed nodes.
var width = 700,
height = 500;
var mouse = [0,0];
var force = d3.layout.force()
.size([width*2, height])
.gravity(0.05)
.chargeDistance(30)
.friction(0.2)
.charge(function(d){return d.fixed?0:-1000})
.linkDistance(5)
.on("tick", tick);
var drag = force.drag()
.on("dragstart", dragstart);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.on("click", function(){
mouse = d3.mouse(d3.select(this).node()).map(function(d) {
return parseInt(d);
});
graph.links.forEach(function(d,i){
var rn = Math.random()*200 - 100;
d.source.fixed = true;
d.source.px = mouse[0];
d.source.py = mouse[1] + rn;
d.target.y = mouse[1] + rn;
})
force.resume();
d3.selectAll("circle").classed("fixed", function(d){ return d.fixed});
});
var link = svg.selectAll(".link"),
node = svg.selectAll(".node");
var graph = {
"nodes": [
{"x": 469, "y": 410},
{"x": 493, "y": 364},
{"x": 442, "y": 365},
{"x": 467, "y": 314},
{"x": 477, "y": 248},
{"x": 425, "y": 207},
{"x": 402, "y": 155},
{"x": 369, "y": 196},
{"x": 350, "y": 148},
{"x": 539, "y": 222},
{"x": 594, "y": 235},
{"x": 582, "y": 185}
],
"links": [
{"source": 0, "target": 1},
{"source": 2, "target": 3},
{"source": 4, "target": 5},
{"source": 6, "target": 7},
{"source": 8, "target": 9},
{"source": 10, "target": 11}
]
}
function tick() {
graph.nodes.forEach(function (d) {
if(d.fixed) return;
if(d.x<mouse[0]) d.x = mouse[0]
if(d.x>mouse[0]+50) d.x--
})
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
}
function dblclick(d) {
d3.select(this).classed("fixed", d.fixed = false);
}
function dragstart(d) {
d3.select(this).classed("fixed", d.fixed = true);
}
force
.nodes(graph.nodes)
.links(graph.links)
.start();
link = link.data(graph.links)
.enter().append("line")
.attr("class", "link");
node = node.data(graph.nodes)
.enter().append("circle")
.attr("class", "node")
.attr("r", 10)
.on("dblclick", dblclick)
.call(drag);
.link {
stroke: #ccc;
stroke-width: 1.5px;
}
.node {
cursor: move;
fill: #ccc;
stroke: #000;
stroke-width: 1.5px;
opacity: 0.5;
}
.node.fixed {
fill: #f00;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<body></body>
I am having problems on setting the data that appear on the xAxis. At this momment I am using the Time in seconds, at this point everything is correct and the data is set aright but in the xAxis I would like to have the time in minutes from the first one, instead of the seconds on I calculate the position. I am wondering if it is posible or I have to re-do the xScale.
var xScale = d3.scale.linear()
.domain([
d3.min(ds, function(d, i){ return d.Seconds - 100;}),
d3.max(ds, function(d){ return d.Seconds})
])
.range([
w - padding,
padding + 100,
]);
var yScale = d3.scale.linear()
.domain([
1 ,
d3.max(ds, function(d){ return d.Place + 2; })
])
.range([ padding, h - padding ]);
Another question I have is that now, I set a function that makes the name and the dots appear bigger on mouseover, Is it possible to make it both at the same time? this is the piece of code on I have it set, but as I did the dots and the labels separetly I cannot see how to connect them.
var dots = svg.selectAll("circle")
.data(ds)
.enter()
.append("circle")
.attr({
cx: function(d, i){ return xScale(d.Seconds); },
cy: function(d){ return yScale(d.Place); },
r: 5,
fill: function(d) { return doping(d.Doping);}
})
.on("mouseover", function(d){
d3.select(this).attr({
r: 7
});
})
.on("mouseout", function(d){
d3.select(this).attr({
r: 5
})
});
/* - - - Labeling the chart - - - */
var labels = svg.selectAll(".label")
.data(ds)
.enter()
.append("text")
.text(function(d){ return d.Name; })
.attr({
x: function(d){ return xScale(d.Seconds) + 20; },
y: function(d){ return yScale(d.Place)+5;},
"class": "label",
"font-size": "10px",
"font-family": "sans-serif",
"text-anchor": "start",
"fill": "#666666"
})
.on("mouseover", function(d){
d3.select(this).attr({
"font-size": "14px"
});
})
.on("mouseout", function(d){
d3.select(this).attr({
"font-size": "10px"
})
})
}
CodePen: http://codepen.io/DiazPedroAbel/pen/xEgNrR
There are several ways for achieving the effect that you ask in your second question ("I set a function that makes the name and the dots appear bigger on mouseover, Is it possible to make it both at the same time?"), such as using groups. I particularly like a different approach, using classes to select all elements I want at once:
First, we set the same class for the circles and the texts:
class: function(d, i){ return (d.Name).split(" ").join("") + i}
Then, inside the mouseover, we retrieve the class:
var thisClass = d3.select(this).attr("class");
And use it for changing both circles and texts.
For your first question, if I understand it correctly (maybe not), you are already showing the time in seconds. So, all you need is to divide it by 60:
var xAxisGen = d3.svg.axis()
.scale(xScale)
.orient("bottom")
.ticks(8)
.tickFormat(function(d){ return d/60});
Here is your codepen: http://codepen.io/anon/pen/dpvxxb?editors=1010
I am using the following code to try to draw a path using d3.js
I have tried various code examples on the web about the same and have been getting the same error everywhere.
Following is the JS:
<script type="text/javascript">
var svg;
//The data for our line
lineData = [ { "x": 1, "y": 5}, { "x": 20, "y": 20},
{ "x": 40, "y": 10}, { "x": 60, "y": 40},
{ "x": 80, "y": 5}, { "x": 100, "y": 60}];
//This is the accessor function we talked about above
var lineFunction = d3.svg.line()
.x(function(d) { return d.x; })
.y(function(d) { return d.y; })
.interpolate("linear");
//The SVG Container
var svgContainer = d3.select("body").append("svg:svg")
.attr("width", 200)
.attr("height", 200);
//The line SVG Path we draw
var lineGraph = svgContainer.append("path")
.attr("d", lineFunction(lineData))
.attr("stroke", "blue")
.attr("stroke-width", 2)
.attr("fill", "none");
</script>
The error is: Uncaught TypeError: Cannot read property 'line' of undefined
This comes at the following line: var lineFunction = d3.svg.line()
I am not sure what 'undefined' means here. Any leads?
Reading your comment I suppose you are using D3 v4. As of version 4 there is no d3.svg, hence the error message. The line generator you are looking for is now defined as d3.line().
If you were still using version 3, it would be d3.svg.line() instead.
Also, as other answerers have noted, this will lead to a follow-up error when leaving the rest of the statement untouched as d3.line does not feature a method .interpolate(). D3 v4 has curve factories for this purpose, which are used for interpolation. These factories are supplied to the line generator using line.curve(). D3 v3's .interpolate("linear") now becomes .curve(d3.curveLinear). However, since line.curve() defaults to d3.curveLinear this can safely be omitted in your case.
The statement thus becomes:
var lineFunction = d3.line()
.x(function(d) { return d.x; })
.y(function(d) { return d.y; })
.curve(d3.curveLinear); // Use for clarity, omit for brevity.
Make sure your code has modified in the below syntax since there is no d3.svg in version 4.
var lineFunction = d3.line()
.x(function(d) { return d.x; })
.y(function(d) { return d.y; });
[Update]
Also, if you are using D3js v4, a problem with this statement .interpolate("linear"); will occur with this warning:
d3.line(...).x(...).y(...).interpolate is not a function.
In this new version, .interpolate("linear"); should be changed to:
curve(d3.curveLinear);
As in the description of curveLinear.
There is declared variable inside the anonymous function, which when returns that variable. Problem is that I can't seem to use that variable, because when I try to return it firebug says, that: TypeError: myData is undefined .
This is my code:
select("circle")
.transition()
.attr("r", function(d) {
var myData = d3.select(this).datum();
return myData[0];
} )
.duration(1000);
That return myData[0]; does indeed return first array element, however my animation takes less than 1 second which means that .duration(1000); doesn't get called, because there is an error in that return myData[0]; , which is kind of puzzling.
That's how I attach data to that circle prior the attempt to animate it:
var valuesMatrix = [];
valuesMatrix[0] = [35, 21, 45, 71, 51, 32];
d3.selectAll("circle")
.data(valuesMatrix);
Why return myData[0]; is considered like undeclared even though it returns valid value.
Update. Press on rectangle to see circle animation:
var svgContainer = d3.select("body").append("svg")
.attr("width", 200)
.attr("height", 200);
svgContainer.append("circle")
.attr("cx", 40)
.attr("cy", 40)
.attr("r", 20);
var valuesMatrix = [];
valuesMatrix[0] = [35, 21, 45, 71, 51, 32];
svgContainer.selectAll("circle")
.data(valuesMatrix);
svgContainer.append("rect")
.attr("x", 90)
.attr("y", 10)
.attr("width", 80)
.attr("height", 20)
.on("click", function(d) {
var selectedGroups = d3.selectAll("circle")
.transition()
.attr("r", function(d) {
var myData = d3.select(this).datum();
// return d[0];
return myData[0];
} )
.duration(2000);
});
This Code is jsfiddle - ready.
It seems to be working
http://jsfiddle.net/regpast123/axkbLp45/2/
The error message suggests that you haven't bound any data to the element you're selecting. Furthermore, you can simplify the code:
.attr("r", function(d) { return d[0]; });
Given a datum containing multiple data elements, such as an object or array, is it possible to set multiple attributes on a selection with a single value function?
E.g. something like:
var data = [{ 'x': 10, 'y': 20, 'r': 5 }];
d3.select('body').append('svg').selectAll('circle')
.data(data)
.enter().append('circle')
.attr('cx cy r', function (d) {
return [d.x, d.y, d.r];
});
instead of:
var data = [{ 'x': 10, 'y': 20, 'r': 5 }];
d3.select('body').append('svg').selectAll('circle')
.data(data)
.enter().append('circle')
.attr('cx', function (d) {
return d.x;
});
.attr('cy', function (d) {
return d.y;
});
.attr('r', function (d) {
return d.r;
});
UPDATE (July 8th 2016) This answer applies to d3 v3.x — NOT v4.x. For the latter version, see Tim Hayes's answer, also on this page. Or... just swap attr with attrs in my answer below, and don't forget to require/import/script-embed d3-selection-multi. And... don't miss the bit about using .each, which may be useful to you.
Yeah, it's possible by passing in a hash (like jQuery's css() method):
d3.select('body').append('svg').selectAll('circle')
.data(data)
.enter().append('circle')
.attr({
cx: function (d) { return d.x; },
cy: function (d) { return d.y; },
r: function (d) { return d.r; }
});
This works for style() as well.
If the reoccurring function (d) {} start to feel like too much, this is another approach:
d3.select('body').append('svg').selectAll('circle')
.data(data)
.enter().append('circle')
.each(function (d) {
d3.select(this).attr({
cx: d.x,
cy: d.y,
r: d.r
});
})
NOTE: this feature only exists in d3.js v2.10.0 or higher
This is an old post, but I found it while Googling around for an answer. The accepted answer no longer works in D3 v4.0.
Moving forward, you can do the same by using the attrs() method. But attrs() is only supported if you load the optional d3-selection-multi script.
So using the example above, it would look like this in D3 v4.0:
// load d3-selection-multi as separate script
<script src="https://d3js.org/d3-selection-multi.v0.4.min.js"></script>
d3.select('body').append('svg').selectAll('circle')
.data(data)
.enter().append('circle')
.attrs({
cx: function (d) { return d.x; },
cy: function (d) { return d.y; },
r: function (d) { return d.r; }
});